Method of and apparatus for amplifying electric signal impulses



Sept. 27, 1927.

H. F. HERBIG METHOD OF AND APPARATUS FOR AMPLIFYING ELECTRIC SIGNALIMPULSBS Filed Aug. 26. 1925 Ian I method of and apparatus for ampli Patnteil Sept. 27.1927.

UNITED STATES PATENT OFFICE.

HENRY I. HEBBIG, OI MAPLEWOOD, NEW JERSEY, ASSIGNOB TO THE COMMERCIALCABLE COMPANY, OF NEW YORK,

n. Y., a conrona'rron 0'! NEW YORK.

IETHOD OF AND APPARATUS FOB'AMPLIFYING ELECTRIC SIGNAL IKPULSEB.

Application filed August 2a, 1925. sci-m a. sun.

The invention relates particularly to a shadow may be oscillated on thetwo cells fying electric impulses transmitted as signals. The circuitand apparatus are especially adapted for amplifying electric impulsestransmitted over a submarine cable and also impulses transmitted overconductors in land line telegraphy.

The apparatus consists of a string galvanometer, which is thesignal-receiving instrument; an optical system combined with the stringgalvanometer. and photo-electric cells in circuit with one or morethermionic vacuum tube amplifiers.

The electrical signals transmitted are received by means of the stringgalvanometer, the string conductor of which is suspended in a verystrong magnetic field and is energized to a state of motion by thereceived electric impulses. The. photo-electric cells are illuminated bylight from a suitable light source, after it traverses a path in whichis suspended the string conductor. a suitable optical system beingprovided for this purpose. The illumination of the photo-electric cellsis varied by the movement of the string conductor in the path of light.its shadow being projected on part of the light sensitive substance ofthe photoelectric cells. This variation of the amount of light on thetwo cells causes a variation of potential of the grid filament circuitofa thermionic vacuum tube amplifier. This variation of potential in thegrid-filament circuit causes a variation in the plate circuit of thevacuum tube amplifier. A siphon recorder. relay or other suitablerecording device. may be connected in the plate circuit of the vacuumtube amplifier to record or retransmit the variations of the platecurrent.

The light source and the beam of light therefrom is stationary or fixed.The string conductor is vibrated in its magnetic field and by itsvibrations varies the position of its sharply defined shadow on the twophotoelectric cells. There is no additional burden imposed on the stringconductor and the sensitiveness of the galvanometer is not aftected. Theshadow of. the string conductor is preferably greatly magnified by theoptical. system in order that it may be cast ontwo photo-electric cellsarranged side by side. By means of this arrangement the in response tothe oscillations of the string conductor of the galvanoineter.

In the drawings:

Fig. 1 is a perspective diagrammatic view of a portion of an. apparatusfor carrying out the invention;

Fig. 2 a diagrammatic view of the two photo-electric cells; and

Fig. 3 a diagrammatic view of the electrrcal apparatus showing theseveral circuits.

Referring to Fig. 1,- 1 designates an incandescent lamp which is asource of light energy for the system. 2 designates an optlcal condensersystem. for concentration of the light. 3 designates an adjustablesubstage optical condenser system for concentrating the light in a smallpoint at the string conductor 4. The current at the recelving end of thecable flows through the conductor 4. (See Fig. 3.) 5 designates a strongmagnet which may-be either a permanent magnet or an electromagnet asdesired. The magnet may be of any form. It 1s shown as a horeshoe magnetwith wide gaps between the pole pieces merely for the sake of simplicityand clearness in the drawmgs. In practice the pole pieces would be muchnearer to the string conductor 4 than is indicated in Fig. 1. and of aform to give a very strong magnetic field along the length of the stringconductor. The condenser 3 is adjustably mounted in one of the polepieces axially in line with the condenser 2. In the other pole piece isan adjustable tubular support for housing the optical microscopicobjective system 6. said support being axially in line with thecondenser 3 and the condenser 2. The string conductor 4 is arrangedbetween the pole pieces and passes through the axial line of the opticalsystem. By means of the microscopic obiective system a greatly enlargedsharp image, indicated bv the cross lines 7 of the string conductor 4 isproduced on the surfaces of the two photo-electric cells 8 and oneposition which the imageor shadow of the string conductor 4 may have onthe light sensitive substance 6 and 6 It is obvious that the shadow maybe arranged in other positions, but it is preferred to have the shadowcover approximately one-half of each cell. This is the positionindicated in Fig.

2 and is also the position of the shadow in dicated in Fig. 3.

Part of the light produced by the lamp 1 is focused by means of theoptical condenser system 2 and the optical substage condenser system 3on the string conductor 4. When the current of the cable at thereceiving end flows through the string conductor 4 in the directionindicated by the arrow head 0. the string conductor is deflected in thedirection indicated by the arrow head d. This causes the shadow 7 of thestring conductor 4 to move in one direction. while when the currentabovereferred to flows in the opposite direction to that indicated by thearrow head 0, the string conductor 4 is deflected in the oppositedirection of that indicated by the arrow head d. Tn either case of thedirection of current flow through the string conductor 4. the" stringconductor always moves perpendicular to the direction of the magneticfield proed by the magnet 5. By means of the nucroscopic objectivesystem 6 a sharp image 7 of the string conductor 4 is projected on partof the light sensitive surface of each of the photo-electric cells 8 and9. By referring to Fig. 2, one manner in which the image of the stringconductor 4 is projected on the light sensitive substances 6 and 6 ofthe photo-electric cells, may be observed. The image 7 of the stringconductor 4 is, therefore, moved either to the right or left, dependingupon the direction of current flow through the string conductor 4. EX-ccpt for the dark image 7 of the string conductor 4, the light sensitivesurfaces b and b of the photo-electric cells 8 and 9 are illuminated.The illumination mentioned is caused by the light that traverses theoptical system but which is not interrupted by the string conductor 4.

The circuits connecting the photo-electric cells and the vacuum tubeamplifier are clearly shown in Fig. 3 and the operation of the partswill be clearly understood by reference to that figure.

When there is no incoming signal the dark shadow 7 of the stringconductor 4 is projected so that it lies partially on the lightsensitive surfaces b and b of the photoelectric cells 8 and 9respectively; the remaining light sensitive surfaces of the cells 8 and9 being illuminated by the light that is not interrupted by the stringconductor 4. With this condition, therejs' a steady efiective potentialin the grid filament circuit of the vacuum tube 17. The grid filamentcircuit is as follows: grid 19, through the parallel combination of:battery15, anode a of photo-electric cell 8, cathode b of same cell, andcathode b of photo-electric cell 9, anode a of the same cell, battery16; then through the resistance 22 and to the cathode 18 of the vacuumtube 17. With this steady potential of the grid filament circuit, thereis a steady flow of current in the plate circuit of the vacuum tube 17,caused by the plate battery 23. Under thiscondition part of this platecurrent flows through the windings of the relays 27 and 28. It isdesirable to have no current flowing through the relay windings whenthere is no signal being sent. It is, therefore, necessary to have thepotential at the upper end of the relay winding No. 27 equal to that atthe lower end of. relay winding No. 28. A biasing battery 24 and avariable resistance 25, which are in series, are connected in shunt withthe circuit including the mil-ammeter 26 and relays 27 and 28 in series.The potential and polarity of battery 24 is of such a. value as to justcompensate for the voltage drop across the resistance 25. Or it may bestated otherwise, that the value of the resistance is such that thevoltage drop across its terminals, caused by the current flowing throughit. is equal in numerical value to that of the biasing battery.

en a signal is received, there is an unbalance of the potential acrossthe relay windings, due to the change of the grid potential of thevacuum tube, and current flows in a clockwise or counter-clockwisedirection through the relay windings. depending upon whether thepotential of the grid is greater than or less than the normal value, thenormal value referring to the condition when the mil-ammeter indicateszero.

A mil-ammeter 26 is connected in the circuit as shown, to indicate'whenthere is no current flowing through the relay windings; hence alsoindicating equal potentials at the two extremes of the relay windings.It is convenient for the mil-ammeter 26 to have the zero mark in thecenter of its scale. Any unbalance can then be readily detected.

Current is received through the cable 12, and part of this current flowsthrough the string conductor 4, thence through the BI'ti-. ficial lineto ground. Assume that the direction of current fiow is such as to causethe image 7 of the string conductor 4 to move to the left, decreasingthe illumination on the light sensitive substance I) of thephoto-electric cell 8, and increasing the light on the light sensitivesurface I) of the photoelectric cell 9. The effective impedance of thephoto-electric cell 8 is greatly increased, while that of thephoto-electric -cell 9f'i's" greatly decreased. This causesthe'potentia-l of the grid 19 to become more positive with respect tothe filament 18. Grid 19 the case previously 'ductor sufficient triccell 8 to increase,

under this condition is also more positive than it was previously when.there was no signal being, received.

The grid 19 becoming more positive than it was originally when there wasno signal being received, the internal impedance of the vacuum tube 17is also correspondingly decreased. Therefore, the plate current islikewise increased, causing the relay or recorder to record orretransmit the signal impulse received.

When the signal is in the opposite direction from that assumed above,the shadow of the string conductor 4 moves to the right, thereby causingthe light on the photo-elecdecreasing its impedance, while the light onthe cell 9 is decreased, causing its impedance to increase. Thepotential of the grid 19 is then decreased in value with respect to thefilament 18 below that which it had been when there was no signal beingsent. The internal impedance of the filament plate circuit of the vacuumtube 17 is increased in value above that which it had when there was nosignal, causing a corresponding decrease in the plate current. Therecorder or relay then operates in an opposite manner to that ofdescribed and records or .retransmits this signal which is alsoo'pposite to that of the first case. In this manner signals of eitherpositive or negative polarity are amplified and recorded orretransmitted.

By giving the shadow of the string con area and suflicient movement oneor the other of the photo-electrlc cells. may be placed completely inshadow for each movement or signal. By total darkness, or excluding thelight from one cell,

the impedance of that cell is so increased that it is cut out of thecircuit and the battery connected thereto is rendered ineffective. It isto be noted that battery 15 has its positive pole connected to the anodea of the cell 8; and that battery-.16 has its positive pole connected tothe anode a of cell 9. With the cell 8 totally eclipsed the battery 15is rendered ineffective in the circuit and the battery 16 thereforeefiectively increases the positive potential of the grid-J19. iVith thecell 9 in total eclipse the battery 16 is rendered ineffective inthe-circuit and the battery 15 then positively and materially increasesthe negative potential of the grid 19. By providing the two sources ofelectric current, that is to say thetwo batteries 15 and 16, andarranging themlin-the circuit as shown in Fig. 3, very positive andmaterial changes in the potential of the grid may be obtained, to theextent of rendering one of said batteries totally ineffective andallowing the other battery to have its full effect upon the grid.

What I claim is: i

1. An apparatus for receiving and amplifying electric signal impulsescomprising a galvanometer having an element adapted to be-vibrated bythe incoming signal impulses and having a normal zero position, meansfor concentrating light rays upon said element whereby said element willcast a shadow and move said shadow as the element vibrates, means foramplifying or enlarging said shadow, a pair of photo-electric cells inthe path of said enlarged shadow whereby a portion of each of said cellswill be covered by said shadow in the normal .position of'the saidelement, a, three-element vacuum tube having its grid-filament circuitconnected to the two photo-electric cells, and means in the platecircuit of said vacuum tube to reproduce amplified signal impulsescorresponding to the impulses received by the galvanometer.

2. An apparatus for receiving and amplifying electric signal impulsescomprising a galvanometer having an element adapted to be vibrated bythe incoming signal impulses and having a normal zero position, meansfor concentrating light rays upon said element whereby said element willcast a shadow and move said shadow as the element vibrates, means foramplifying or enlarging said shadow, a photo-electric cell in thepath'of said enlarged shadow whereby a portion of said cell will becovered by said shadow in the normal position of the said element,. athree-element tube having its grid-filament circuit connected to thesaid photo-electric cell, and means in the plate circuit of said vacuumtube .to reproduce amplified signal impulses corresponding to theimpulses received by the galvanometer.

2}. An apparatus for receiving and amplifying electric signal impulsescomprising a string galvanometer having a string conductor adapted to bevibrated in two directions by the incoming signal impulses and having anormal zero position, means for concentrating light rays upon saidstring conductor whereby sai conductor will cast a shadow, means foramplif ing or enlarging said shadow, a pair 0 photo-electric cells inthe path of said enlarged shadow whereby a portion of each of said cellswill be covered by said shadow in the normal position of the stringconductor, a three element vacuum tube, a battery having its positivepole connected to the anode of one photo-electric cell its negative polebeing connected to the cathode'of the other photoelectric cell andto thegrid of the vacuum tube, a battery having its positive pole connected to"the anode of one photo-electric cell and its negative pole connected tothe cathode of the other photo-electric cell and to the filament of thesaid vacuum tube, whereby the positive pole of one of said batterieswill be connected to the anode of one photo-electric cell, and thepositive pole of the other of saidbatteries will be connected to theanode of the other photoelectric cell, and means adapted to be operatedby the amplified impulses in the plate circuit of the said vacuum tube,said impulses corresponding to the impulses received by thegalvanometer.

4. An apparatus for receiving and amphfying electric signal impulses,comprising a string galvanometer having a string conductor adapted to bevibrated in two directions by the incoming signal impulses and having anormal zero position, means for concentrating light rays upon saidstring conductor whereby said conductor'will cast a shadow, means foramplifying or enlarging said shadow, a pair of photo-electric cells inthe path of said enlarged shadow whereby a portion of each of said cellswill be covered by said shadow in the normal position of the stringconductor, a three-element vacuum tube, a battery connected to eachphoto-electric cell, the positive pole of one of said batteries beingconnected to the anode of one photo-electric cell and the positive poleof the other of said batteries being connected to the anode of the otherphoto-electric cell, and means adapted to be operated by the amplifiedimpulses in the plate circuit of the said vacuum tube, said impulsescorresponding to the impulses received by the galvanometer.

5. The method of receiving and amplifying electric impulses, consistingin producing a constant normal flow of electrons in a light sensitiveelectron discharge device by partially illuminating said device from afixed source of light and partially darkening said device by a sharplydefined shadow of a vibratory impulse-receiving element, causing avariation in said electron flow by mov ing the shadow to cover more orless of said device as the impulse receiving element is vibrated by thereceived impulses, and then utilizing the variations in the saidelectron flow to control means to reproduce and amplify impulses pulsesreceived.

6. An apparatus for receiving and amplifying electric signal impulsescomprising a string galvanometer having a string conductor adapted to bevibrated in two directions by the incoming signal impulses from a normalzero position, means for c0ncentrating light rays upon said stringconductor whereby said conductor will cast a shadow and move said shadowas the conductor vibrates, means for amplifying or enlarging saidshadow, a pair of photo-electric cells in the path of said enlargedshadow whereby a portion of each of said cells will be covered by saidshadow in the normal position of the string cnductor, a thermionicvacuum tube amplifier having its grid-filacorresponding to the immentcircuit connected to the two photoelectric cells, and means in the platecircuit of said vacuum tube to reproduce amplified signal impulsescorresponding to the impulses received by the string conductor.

An apparatus for receiving and amplifying electric signal impulsescomprising a string galvanometer having a string conductor adapted to bevibrated by the incoming signal impulses and having a normal zeroposition, means for concentrating light rays upon said string conductorwhereby said conductor will cast a shadow and move said shadow as theconductor vibrates, means for amplifying or enlarging said shadow, aphoto-electric cell in the path of said enlarged shadow whereby aportion of said cell will be covered by said shadow in the normalposition of the string conductor, a thermionic vacuum tube amplifierhaving its grid-filament circuit connected to the said photo-electriccell, and means in the plate circuit of said vacuum tube to reproduceamplified signal impulses corresponding to the impulses received by thestring conductor.

8. An apparatus for receiving and amplifying electric signal impulsesstring galvanometer having a string conductor adapted to be vibrated bythe incoming signal impulses and having a normal zero position, meansfor concentrating light rays upon said string conductor whereby saidconductor will cast a shadow and move said shadow as the conductorvibrates,- means for amplifying or enlarging said shadow,

comprising a a photo-electric cell in the path of said enlarged shadowof the string conductor, a

thermionic vacuum tube amplifier having its grid-filament circuitconnected to the said photo-electric cell, and means in the platecircuit of said vacuum tube to reproduce amplified signal impulsescorresponding tothe impulses received by the string conductor.

9. An apparatus for receiving and amplifying electric signal impulses,comprising a galvanometer having an element in a normal zero positionand adapted to be vibrated by incoming signal impulses; means forconcentrating light rays upon said element whereby said element willcast a shadow and vary said shadow as the element vibrates; aphoto-electric cell in the path of said shadow, whereby a portion ofsaid cell will be covered by said shadow in the normal position of thesaid element and more or less of said cell Will be affected by saidshadow as the element vibrates; a three-element tube hav-.

plifying electric signal impulses, comprising a galvanometer having anelement in a normal zero position and adapted to be vibrated by incomingsignal impulses; means for concentrating light rays upon said elementwhereby said element will cast a shadow and vary said shadow as theelement v1- brates; a pair of photo-electric cells n the path of saidshadow, whereby a portion of each of said cells will be covered by saidshadow in the normal position of the said element and more or less ofsaid cells will be affected by said shadow as the element v1- brates; athreeelement vacuum tube having its grid-filament circuit connected tothe said two photo-electric cells; and means in the plate circuit ofsaid vacuum tube to reproduce amplified signal impulses corresponding tothe impulses received by the galvanometer.

11. An apparatus for receiving and amplifying electric signal impulses,comprising a galvanometer having an element ina normal zero position andadapted to be vibrated in one direction by an incoming signal impulse ofpositive current and to be vibrated in the opposite direction by anincoming signal impulse of negative current; means for concentratinglight rays upon said element whereby saidelement will cast a shadow andmove said shadow as the element vibrates; means for amplifying orenlarging said shadow; a photo-electric cell in the path of saidenlarged shadow whereby a portion of said cell will be covered by saidshadow in the normal position of the said element; a three-element tubehaving its grid-filament circuit connected to the said photo-electriccell; and means in the plate circuit of said vacuum tube to reproduceamplified signal impulses corresponding to the impulses received by thegalvanometer.

12. An apparatus for receiving and amplifying electric signalimpulses,-comprising a galvanometer having an element in a normal zeroposition and adapted to be vibrated in one direction by an incomingsignal ini pulse of positive current and to be vibrated in the oppositedirection by an incoming signal impulse of negative current; means forconcentrating light rays uponsaid element whereby said element will casta shadow and move said shadow as the element vibrates; means foramplifying'or enlarging said shadow; a pair of photo-electric cells inthe path of said enlarged shadow whereby a portion of each of said cellswill be covered by said shadow in the normal position of the saidelement; a three-element vacuum tube havin its grid-filament circuitconnected to t e said two photo-electric cells; and means in the platecircuit of said vacuum tube to reproduce amplified signal impulsescorresponding to the impulses received by the galvanometer.

13. The method of receiving, amplifying and reproducing electric signalimpulses, consisting in producing a sharply defined shadow of thevibrating element of a sensitive receiving instrument adapted to bevibrated in two directions from normal or zero position by positive andnegative current impulses; arranging the vibrating element of thereceiving instrument to vibrate freely and thereby retain-itssensitiveness unrestricted and unimpaired; causing said vibratingelement to cast a shadow and move said shadow as the vibrating elementis moved; causing said shadow in its normal or zero position topartially darken a lightsensitive cell to thereby produce a constantnormal flow of electric current through said cell, the current flowbeing varied as the shadow is caused to affect more or lessof the saidcell through the vibrations of the vibrating element of the receivinginstrument; and then utilizing the variations of the said current flowto control means to reproduce and amplify impulses corresponding inchar-'- acter and duration to the impulses which caused the movement ofthe vibrating element of the receiving instrument.

14. The method of receiving, amplifying and reproducing electric signalim ulses, consisting in producing a sharply shadow of the vibratingelement of a sensitive receiving instrument adapted to be vibrated fromnormal or zero position by received current impulses; arranging thevibrating element of thereceiving instrument to vibrate freely andthereby retain its sensitiveness unrestricted and unimpaired causingsaid vibrating element to cast a shadow and move said shadow as thevibrating element is moved; causing said shadow in its normal or zeroposition to partially darken a light-sensitive cell to thereby produce aconstant normal flow of electrons in said cell, the electron flow beingvaried as the shadow is caused to affect more or less of the said cellthrough the vibrations of the vibrating element of the receivinginstrument; and then utilizing the variations of the said electron flowto control means to reproduce and amplify impulses corresponding incharacter and duration to the impulses which caused the movement of thevibrating element of the receiving instrument.

15. The method of receiving, reproducing and amplifying electric signalimpulses, conreproducing means to afl'ect said amplifying andreproducing means by light rays to reproduce the received signalimpulses without mechanical or electrical connection between thevibrating element of the receiving apparatus and the amplifying andreproducing apparatus.

16. The method of receiving, reproducing and amplifying electric signalimpulses, consisting in rece ving said signal impulses on asignal-receiving device having a freely vibrating element in a normalzero position and adapted to be freely vibrated by current impulses, andthereb retain its sensitiveness unimpaired, where y said element willnot be retarded in its movements; and associating the said vibratingelement of the receiving instrument with an optical system and with anamplifying and reproducing means to affect said amplifying andreproducing means by light ra s to reproduce the received si al impuses, whereby the amplifying an reproducing means will be operatedwithout mechanical or electrical connec- 25 nection between thevibrating element of the receiving apparatus and the amplifying andreproducing a paratus.

17. The met 0d of receiving, reproducing and amplifying electric signalimpulses of positive, negative and zero current character, consisting inreceiving said signal impulses on a sensitive signal-receiving devicehaving a vibrating element in a normal zero position and adapted to bevibrated in one direction by positive current impulses and to bevibrated in the opposite direction by negative current impulses; andarranging said vibrating element of the receiving instrument to vibratefreely in'an optical system to afi'ect an amplifying and reproducingmeans by light rays without reducing the sensitiveness of the vibratingelement and without mechanical or electrical connection between thevibrating element of the receiving apparatus and the amplifying andreproducing apparatus.

In testimony whereof I hereunto afiix my signature.

HENRY F. HERBIG]

